Telecommunications systems, cable television systems and data communication networks use optical networks to rapidly convey large amounts of information between remote points. In an optical network, information is conveyed in the form of optical signals through optical fibers. Optical fibers comprise thin strands of glass capable of communicating the signals over long distances with very low loss.
To ensure high reliability and availability in communications networks, including optical communications networks, redundancy is often built into such networks, so that if a fault occurs in a particular communications path, a redundant backup communication path may be utilized. In mesh networks, utilization of a backup path in response to a fault in a primary path may be referred to as “mesh restoration.”
In order to provide mesh restoration at the physical optical layer in a networking stack, specific constraints (e.g., reconfigurable optical add/drop multiplexer or ROADM constraints such as color constraints or direction constraints, for example) may require that extra transponders be pre-installed to support restoration demands of an optical network. Using known techniques for providing restoration demands in a colored, directional ROADM network, at least a pair of backup transponders may be required for each working demand in the network, thus doubling the number of installed transponders, leading to a very costly network solution.